This invention relates to photonic devices in general, and more particularly to tunable lasers.
In pending prior U.S. patent application Ser. No. 09/105,399, filed Jun. 26, 1998 by Parviz Tayebati et al. for MICROELECTROMECHANICALLY TUNABLE, CONFOCAL, VERTICAL CAVITY SURFACE EMITTING LASER AND FABRY-PEROT FILTER, and in pending prior U.S. patent application Ser. No. 09/543,31, filed Apr. 5, 2000 by Peidong Wang et al. for SINGLE MODE OPERATION OF MICROMECHANICALLY TUNABLE, HALF-SYMMETRIC, VERTICAL CAVITY SURFACE EMITTING LASERS, which patent applications are hereby incorporated herein by reference, there are disclosed tunable Fabry-Perot filters and tunable vertical cavity surface emitting lasers (VCSEL""s).
More particularly, and looking now at FIG. 1, there is shown a tunable vertical cavity surface emitting laser (VCSEL) 5 formed in accordance with the aforementioned U.S. patent applications Ser. Nos. 09/105,399 and 09/543,318. VCSEL 5 generally comprises a substrate 10, a bottom mirror 20 mounted to the top of substrate 10, a gain medium (or xe2x80x9cactive regionxe2x80x9d) 23 mounted to the top of bottom mirror 20, a bottom electrode 15 mounted to the top of grain medium. 23, a thin support 25 atop bottom electrode 15, a top electrode 30 fixed to the underside of thin support 25, a reinforcer 35 fixed to the outside perimeter of thin support 25, and a confocal top mirror 40 set atop thin support 25, with an air cavity 45 being formed between bottom mirror 20 and top mirror 40.
As a result of this construction, when active region 23 is appropriately stimulated, e.g., by optical pumping or electrical current, lasing can be established within air cavity 45, between top mirror 40 and bottom mirror 20. Furthermore, by applying an appropriate voltage across top electrode 30 and bottom electrode 15, the position of top mirror 40 can be changed relative to bottom mirror 20, whereby to change the length of the laser""s resonant cavity, and hence tune VCSEL 5.
The present invention is directed to VCSEL""s which are constructed so as to have their active region stimulated by optical pumping.
The primary object of the present invention is to provide a novel method for modulating the output of an optically pumped, tunable VCSEL.
Another object of the present invention is to provide a novel method for modulating the output of an optically pumped, tunable VCSEL by modulating the pump laser.
And another object of the present invention is to provide a novel method for modulating the output of an optically pumped, tunable VCSEL by modulating a voltage applied across the active region.
These and other objects are addressed by the present invention.
In one form of the invention, there is provided a method for modulating the output of an optically pumped, tunable VCSEL, wherein the method comprises the steps of: (1) optically pumping the VCSEL with a pump laser so as to cause the VCSEL to generate an output; and (2) modulating the output light power of the pump laser so as to modulate the carrier population in the VCSEL""s active region whereby to modulate the output of the VCSEL.
In another form of the invention, there is provided a method for modulating the output of an optically pumped, tunable VCSEL, wherein the method comprises the steps of: (1) optically pumping the VCSEL with a pump laser so as to cause the VCSEL to generate an output; and (2) applying a voltage across the active region so as to alter the optical power circulating in the VCSEL""s cavity, whereby to increase or decrease the output power of the VCSEL.